| The first part of this dissertation focuses on the research of efficient broadband Terahertz microstrip waveguides. I propose a novel subwavelength microstrip architecture for efficient broadband THz waveguides that utilizes dipole antennas at the input-face for enhanced THz coupling. This compact optoelectronic device utilizes a metal dipole antenna on the input face of substrate to couple freely propagating THz pulses into the subwavelength structure, and employs a microstrip line structure to guide the THz signals along the desired path. I will discuss both experimental and simulation results, which demonstrate the capability of this microstrip structure to operate as an efficient broadband terahertz waveguide.;The second part of this dissertation presents our research on the role of metal film thickness on the enhanced transmission properties of a periodic array of subwavelength apertures. I have measured the enhanced transmission properties of periodic arrays of subwavelength apertures fabricated in thin metal films as a function of the metal film thickness. The thickness range explored extends from lambda/15, where lambda is the skin depth, to approximately 2pi. Experimentally, we find that there is negligible transmission enhancement for metal films as thin as lambda/15. For metal films thicker than one skin depth, there appears to be little additional enhancement at the resonant frequencies.;The third part of this dissertation describes our investigation on the phase sensitive terahertz transmission properties of split ring resonator array. I have measured the transmission properties of double-ring split ring resonator (SRR) arrays and closed ring resonator arrays using terahertz (THz) time domain spectroscopy. We find that the electric field, when appropriately polarized, can couple to the magnetic resonance. I measure shifts in the resonance properties with changes in the SRR dimensions and the substrate medium. The results are consistent with theory. |
